1. Field of the Invention
The present invention relates to a manufacturing method of a semiconductor substrate provided with a single crystal semiconductor layer over an insulating surface and a manufacturing method of a semiconductor device.
2. Description of the Related Art
As an alternative to an integrated circuit using a silicon wafer which is manufactured by thinly slicing an ingot of a single crystal semiconductor, an integrated circuit using a semiconductor substrate that is referred to as a silicon-on-insulator (hereinafter also referred to as “SOI”) substrate, in which a thin single crystal semiconductor layer is provided on an insulating surface has been developed. The integrated circuit using an SOI substrate has attracted attention as an integrated circuit which reduces parasitic capacitance between a drain of a transistor and the substrate and improves the performance of a semiconductor integrated circuit.
As a method of manufacturing an SOI substrate, a hydrogen ion implantation separation method is known (for example, see Patent Document 1). In the hydrogen ion implantation separation method, hydrogen ions are added to a silicon wafer surface to form a microbubble region at a predetermined depth from the surface, and then the silicon wafer surface is bonded to another silicon wafer. By further performing a heat treatment, hydrogen ions that are distributed in the silicon wafer become concentrated in the microbubble region, and by the microbubble region becoming a cleaved surface and a silicon layer on a surface side getting separated at the cleaved surface, the separated thin silicon layer can be transferred the silicon wafer to which it is bonded.